N-tiers Design Series (II): three-tier Application System Architecture

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If ASP is used to process web application systems with complex business logic, the following disadvantages may occur:

1. Complicated ASP content: If complicated data processing is required, ASP will become much more complicated.

2. Security: Writing Data Reading and maintenance in ASP is not safe because hackers may find your aspProgramTo know your database, data table, fields, and even your business logic.

3. transaction processing is not easy: If you need to maintain multiple data tables or even multiple databases, so we need to maintain the integrity of the data changes (all data tables are successfully maintained. As long as one of the links fails, the data to be maintained must be restored)

Therefore, in response to the above requirements, we have a three-tier Web application system architecture.

Split the web application system into three parts

1. interface layer (IIS): This layer is used to generate user interfaces and data display interfaces, and retain the original parts of ASP for image processing in this layer.

2. Data Layer (db): Used to add, modify, delete, and query data

3. Business logic layer (COM +): As for complex work such as review data processing, business logic, and data change consistency, it is handled by the intermediate [business logic layer.

The business logic layer is a component written in VB, C, or other languages. It is a compiled DLL and a literal translation language (compilation started only when executed) with ASP) high performance. In addition, the compiled DLL is registered in [Component Service (COM +)], and the integrity of data changes is handled through COM +, which is much easier for development programs. For details about the integrity of data changes, the method of program writing, and the method of component registration, the following sections will be introduced one after another.